After the candles you need to find ritual powder which activates after reading "dead girl's" note. And the darkness was kind of what I was going for, because I didn't want to reveal much in the scene, but I guess I could just make a lighting setting. Thanks for the tip :)
Yeah, I'll keep this in mind for dark scenes. So after the note find the powder and if all the candles are in place you can activate the thing in the middle, just toggle your crappy flashlight at the thing if it doesn't show the interaction icon :)